Chlamydia and gonorrhea are not diseases you want to tangle with. Infections with either may make HIV easier to catch and transmit, and both can cause infertility and chronic pelvic pain in women. But both are easily treated with antibiotics. Researchers at the University of North Carolina and the University of Washington looked at prevalence of the diseases among young adults.

What the researchers wanted to know: How common are chlamydia and gonorrhea among young people in the United States?

What they did: In the third wave of interviews of the National Longitudinal Study of Adolescent Health, interviewers visited 14,322 young adults ages 18 to 26 at home. (Respondents got to answer the potentially embarrassing sexual questions on a computer.) Eighty-eight percent of the interviewees also gave urine samples.

What they found: A lot of young adults had chlamydia—about 4 percent. The rate was more than six times higher in black young adults than in white young adults and higher among women than men; nearly 14 percent of young black women were infected. Gonorrhea was much less common, with less than half a percent infected overall, but that rate also varied by race—about 2 percent of black men and women were infected, compared with about one-tenth of 1 percent of whites.

What this study means to you: The high rate of chlamydia infection suggests that we aren't doing a good enough job at catching and treating the disease. Chlamydia may cause infertility and ectopic pregnancies—and these results could explain why black women have a higher rate of ectopic pregnancy than white women.

Caveats: Since the people in the survey were chosen many years ago and many refused to continue or couldn't be found again, the dropouts could have biased the sample‑but the researchers allowed for that in their analysis.

Find out more: Read the abstract of the article for free at http://jama.ama-assn.org/

Chlamydia fact sheet from the National Institute of Allergy and Infectious Diseases: http://www.niaid.nih.gov

Read the article: Miller, W.C. et al. "Prevalence of Chlamydial and Gonococcal Infections Among Young Adults in the United States". Journal of the American Medical Association. May 12, 2004, Vol. 291, No. 18, 2229–2236.